Measurements of systemic hemodynamics and left ventricular function in human septic shock have shown that the usual hemodynamic pattern is a hyperdynamic cardiovascular state with reversible depression in left and right ventricular ejection fraction. Because of the major role of cytokines in experimental septic shock, we are evaluating functional and immunogenic activity of cytokines including tumor necrosis factor, interleukin-1, 6 and will relate these measures to the development of cardiovascular dysfunction in human sepsis. The goal of this study is to understand the pathogenesis of septic shock better so that new therapies can be developed.